Figure 3. Streamer nozzle 



reverses. The stainless steel rack holds each nozzle and streamer securely at 

 a particular elevation in the flow. The 40 -cm- long rack legs are embedded in 

 the sand bed during use for stabilization of the trap. The streamers have an 

 end which can be untied and opened to remove collected sand; during operation, 

 the streamer is closed by folding the end of the cloth over on itself then 

 looping an attached nylon string around the gathered end and tying it securely 

 (Figure 4) . 



Figure 4. Method of closing streamer 



15 



